Family of 6 going to Sesame Pl. looking for other things to do while in Penn.?

Without knowing where you're coming from, I'll assume you're looking for things to do in and around Sesame Place rather than places to stop on your way home. Obviously, Philadelphia and its various downtown attractions (Liberty Bell, Independence Hall, Franklin Institute Science Museum, Adventure Aquarium, etc.) can easily eat up a day or two of your PA itinerary. The wider Philly metro area also offers an interesting mix of outdoor and cultural attractions; the website for the Great Philadelphia area (www.gophila.com) is a good place to dig up some ideas, as is the tourism website for Bucks County (www.visitbuckscounty.com).